Natural gas vehicles are vehicles that use natural gas as a fuel that ultimately powers the vehicle to cause the vehicle to move. As used herein, a vehicle is a movable device for transporting people or materials on land, in air, in water, or through space. Examples of vehicles include automobiles, trucks, motorcycles, carts, wagons, trains, aircraft, missiles, ships, boats, submarines, and spaceships.
The natural gas may fuel an internal combustion engine that drives a powertrain and causes a drive wheel or propeller to turn. The natural gas may also be used to power an on-board generator that provides electrical power to an electric motor that causes a drive wheel or propeller to turn. Natural gas may be used to power a fuel cell that provides electrical power to an electric propulsion motor.
Natural gas may be stored in cylindrical pressure vessels, or vessels having any suitable shape. For example, a natural gas storage vessel may be spherical, cubic, or any other shape, regular or irregular, that can enclose a volume. When natural gas is stored at high pressure, cylindrical and spherical storage vessels tend to be chosen because of the stress-handling characteristics of cylinders and spheres. However, packaging large cylinders and spheres in an automobile has heretofore resulted in reductions in space available for occupants or for cargo.
Some aspects of certain cylindrical pressure vessels are referenced by a “Type number” as defined by ISO (International Organization for Standardization). According to ISO 11439-Second Edition, a gas cylinder of Type 1 design is an all metal cylinder. A Type 2 design is a hoop wrapped cylinder with a load sharing metal liner and composite reinforcement on the cylindrical part only. A Type 3 design is a fully wrapped cylinder with a load sharing metal liner and composite reinforcement on both the cylindrical part and dome ends. A Type 4 design is a fully wrapped cylinder with a non-load sharing liner and composite reinforcement on both the cylindrical part and dome ends.